The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures to manufacture power supply controllers that regulated current for a power supply system. These were often referred to as current regulators. The current regulators generally switched a power transistor to control current flow through an inductor in order to regulate a current to a desired value. In order to measure or determine the value of the current through the inductor, the system typically utilized a device external to the current regulator such as a current sense winding of a transformer or a resistor in series with the power transistor or the inductor. The current regulator used this measured value to control the current. The elements used to sense the current, such as the current sense transformer and current sense resistor, added cost to the system. Additionally, the current sense resistor could add additional power dissipation.
Accordingly, it is desirable to have a method of determining current flow for a current regulator that uses fewer components externally to the controller and that has a lower cost.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay between the reaction that is initiated by the initial action.